1. Field of the Invention
This invention relates generally to flotation sleep systems and more particularly to a waterbed mattress having a stacked arrangement of fluid filled containers laterally supported within a rigid frame structure.
2. Description of Related Art
Over the past twenty (20) years waterbeds have enjoyed increasing popularity since they provide both personal and therapeutic comfort through buoyant support not offered by conventional spring mattresses. Conventional waterbed structures consist of a unitary water filled bladder with some type of retaining wall to laterally support the bladder therein to a confined area. Typical examples of such conventional structures are disclosed in Fox, Jr. et al, U.S. Pat. No. 4,186,455, Autrey et al, U.S. Pat. Reissue No. 32,420, Johenning, U.S. Pat. No. 4,197,602 and Santo, U.S. Pat. No. 4,334,331. The waterbed structures disclosed in these patents, however, all suffer from several of the following disadvantages, namely, wave motion, excessive weight, bowing of retaining walls, difficulty in moving, filling and emptying, limited buoyancy adjustment, hardness, mattress water leaks and multiple user wave motion discomfort.
Attempts have been made to eliminate one or more of these disadvantages with limited success. For example, Echevarria, U.S. Pat. No. 4,221,013 discloses a waterbed structure including a foam box filled with a series of elongated water filled containers. Leaks are limited to each separate container and wave motion is reduced. However, although wave motion may be confined principally within individual containers, there is still considerable wave motion within each container especially along the longitudinal extent of such containers. Additionally, it is very difficult to fill each and every container with the same amount of water. Uneven filling causes the buoyancy support provided by the mattress and therefore the comfort to change over the sleeping area of the bed.
More progressive attempts to develop a waterbed structure include mattress arrangements which have both water chambers and air chambers as disclosed in Linder U.S. Pat. No. 4,558,476, Barbulla U.S. Pat. No. 4,638,518 and Shields, U.S. Pat. No. 3,766,579. In Linder, a waterbed configuration is disclosed including a fluid filled envelope wherein are suspended resilient material, and an air mattress located beneath the resilient material. Valves are coupled to the various chambers to vary the pressure and consequently the supporting forces in each chamber. Barbulla discloses a mattress comprising at least three intergral chambers: one chamber being divided into upper and lower water filled chamber portions, the lower chambers containing particulate buoyant materials; the other chambers being filled with air, which chambers are located along the longitudinal sides of the mattress and at the bottom of the mattress. Shields discloses a waterbed comprising an air beam structure which acts as the supporting frame. The air beam incorporates a bottom sheet to retain any leaking water. An air mattress is positioned within the frame work of the air beam, and the air mattress supports a water filled envelope positioned thereupon.
Unfortunately while certain disadvantages are overcome by these water and air chambered waterbed structures, the patented structures result in additional disadvantages which render them commercially undesirable for providing substitutes for the relatively inexpensive conventional waterbed described above. For example, in each instance structure the mattress bladder is much more complex than conventional structures and not conducive to low cost manufacturing techniques.
While many waterbed structures have evolved over the last 20 years, no inexpensive, yet reliable waterbed structures have been realized to effectively deal with many of the aforementioned disadvantages which have plagued the industry for many years.